1. Field of the Invention
The present invention relates to an engine control apparatus, and more particularly, to a control apparatus that detects and/or corrects variations in both the amount of fuel and the amount of air among cylinders.
2. Background Art
Against a background of problems with the global environment, there is an ever increasing demand for automobiles emitting less exhaust and less CO2 (less fuel consumption). In order to improve performance of engines, engines provided with a mechanism that controls the amount of fuel and amount of air supplied to the engine independently of each other, for example, by adopting a variable valve, are becoming widespread. In such engines, it is necessary to guarantee the performance of controlling the amount of fuel and the amount of air independently of each other in a practical environment, too.
JP Patent Publication (Kokai) No. 2004-346807A discloses an invention that detects, when a difference between an average value of a target air-fuel ratio and that of a real air-fuel ratio over a predetermined period exceeds a predetermined value, an abnormal cylinder based on a rotation variation and corrects the air-fuel ratio of the cylinder based on a fuel injection amount.